This invention relates to valves and, more particularly, to an improved primer valve.
For some types of engines, such as small internal combustion engines, a primer system is used to assist in starting the engine. Such priming systems are arranged to introduce a small quantity of fuel directly into the engine intake manifold valve downstream of the carburetor with the admission of the priming fuel being controlled by a primer valve. Primer valves typically include a spring-loaded check valve in the outlet which is opened when the upstream pressure exceeds the engine intake manifold pressure and overcomes the force of the check valve spring. It is often difficult to build up sufficient pressure to open the check valve, especially when vapors are present in the priming system. Also, this check valve can open inadvertently under high vacuum conditions in the intake manifold during engine operation and allow unwanted fuel to be drawn through the primer valve into the engine intake manifold.
U.S. Pat. No. 3,534,768 discloses a check valve.